On July 30, 1994, at 1455 Pacific daylight time, a Cessna 182P, N20707, sustained substantial damage during a forced landing at Livermore, California. The aircraft was operated and flown by the owner and was on a personal cross-country flight. Visual meteorological conditions prevailed at the time and no flight plan had been filed. The certificated airline transport pilot sustained serious injuries. The flight originated from the Reid-Hillview airport San Jose, California, at 0545 on the day of the accident and had made an enroute stop in Livermore. The Federal Aviation Administration (FAA), Air Traffic Control Tower (ATCT), local controller reported that the aircraft departed Livermore Municipal airport on runway 25R, climbing to about 500 feet agl. The pilot stated that his engine began to run rough during the climb out. He switched his fuel selector from the "both" position to "right" and made a distress call on the tower frequency. The local controller cleared the aircraft to land on runway 7L. The pilot attempted to make a 180-degree turn back to the airport; however, he said he did not have sufficient power or altitude available to reach the runway. Witnesses reported that the aircraft appeared to stall at low altitude then impacted in an open field approximately 500 feet short of the departure end runway. An FAA inspector examined the aircraft after the accident and reported that fuel was seeping from the left main fuel tank vent line. He observed recovery personnel drain approximately 15 gallons of fuel from the left main tank into temporary storage containers. The inspector also reported that the aircraft's fuel selector valve was positioned on the right main fuel tank. During a visual inspection of the right main fuel tank, he was unable to detect any visible fuel. A post accident inspection of the aircraft revealed no mechanical engine or related system abnormalities. Further inspection of the aircraft fuel system revealed that the carburetor bowl was full of what appeared to be automotive fuel. The bowl was free of visible contaminants and the main carburetor jet was unobstructed. The gascolator drain was found jammed partially open and approximately 1/4 inch of fuel was in the gascolator bowl. The gascolator bowl was free of visible contaminants. The fuel line between the fuel selector and the common feed line from the right tank was crushed and buckled near the selector valve. There were no leaks or blockages found in any of the fuel lines or either tank. The aircraft owner's manual states that the capacity of each main tank is 32.5 gallons with 2.5 gallons unusable. The manufacturers representative stated that the final position of the aircraft after the mishap with a left wing low, nose low attitude, would be sufficient to allow previously unusable fuel in the right tank to flow from that tank through the selector to the carburetor.